Apparent diffusion coefficient determination of sodium hydroxide through potato skin and flesh under different temperatures and concentration conditions

The aims of the present study were to analyze the most important chemical reactions between sodium hydroxide and potato constituents involved in potato chemical peeling, and to measure the apparent diffusivity of NaOH in potato skin and flesh separately, as a function of temperature and NaOH concentration, selected according to potato chemical peeling process. Chemical reaction of the suberin of the potato skin with NaOH was proposed as the most important one to promote chemical peeling. Whereas starch hydrolysis, middle lamella dissolution and cell wall disruptions were proposed as the principal chemical reactions in flesh. Experiments to determine NaOH apparent dijfusivities in skin and flesh were performed following a cell diffusion method at 25, 40, 50, 60 and 70 °C temperatures and concentrations of 4, 12 and 20 g NaOH/100 g of solution. Finally, correlation equations were determined to describe apparent diffusivity dependence on temperature and concentration.     

Effects of viscosity on the bitterness and astringency of grape seed tannin

To examine the separate effects of viscosity and sweetness on astringency, aqueous solutions of grape seed tannin (GST) were thickened with carboxymethyl cellulose (CMC) from 2 to 45 cP (experiment 1) or sweetened with 0 to 1.8 g/L aspartame (experiment 2). Trained subjects continuously rated astringency and bitterness in duplicate. Subjects were categorized by the salivary flow induced by citric acid and ability to taste n-propyl thiouracil (PROP). In experiment 1, maximum intensity and total duration of astringency were significantly decreased as viscosity rose, although time to maximum intensity of astringency was not affected. Maximum intensity and total duration of bitterness were not significantly affected by increasing viscosity; however, the onset of bitterness was significantly delayed. In experiment 2, increasing sweetness had no affect on any astringency parameter, although maximum intensity of bitterness was significantly decreased. Neither PROP nor salivary flow-status had any effect on perception of bitterness or astringency in either experiment.     

桌域网及其新技术的研究

桌域网是一种适合于多媒体业务需要的小型ATM网 ,是对传统计算机网络的体系结构的一种补充。本文介绍了设计桌域网的基本策略 ,讨论了它的设计目标和特性 ,给出了桌域网的体系结构、网络接入设备及其性能 ,最后提出研究桌域网的几点建议。     

基于拓扑法的多关节机械手无碰路径规划

本文提出了一种基于拓扑法的多关节机械手无碰路径规划方法,文中重点讨论了三关节机械手路径规划时如何划分状态空间、判别各连通块之间的连通性以及路径搜索等问题,最后我们给出了一个实验结果以示该方法的有效性。     

颗粒类型对颗粒增强铝基复合材料性能的影响

本文对粉末冶金法制备的ＳｉＣ和ＴｉＣ颗粒增强铝基复合材料进行了研究。试验表明，在颗粒含量相同、尺寸相当的条件下，ＴｉＣ增强Ａｌ基复合材料的强度和模量均低于ＳｉＣ增强Ａｌ基复合材料，但其屈强比却明显高于ＳｉＣ增强Ａｌ基复合材料。高温长时间等温处理对ＴｉＣ颗粒增强纯Ａｌ复合材料的强度没有明显的影响。     

CETRAN系统中的英语词汇结构与功能

本文介绍了汉英机器翻译系统中从中间媒介语言生成英语的生成系统的词汇结构和功能，描述了生成系统各个层次之间的转换原理。为了说明清楚，在叙述中注意了列举从中间媒介中间媒介语言到目标语句的生成实例。     

Do antral washouts have a place in the current management of chronic sinusitis?

Antral washouts have been widely used in the management of chronic sinusitis. With the advent of modern antibiotics and powerful topical nasal steroids, we sought to establish if a role remains for this procedure. One hundred and fourteen patients with chronic sinusitis were randomised into two groups. Patients in Group A received antral washouts followed by antibiotics and topical nasal steroids. Patients in the Group B received antibiotics and topical nasal steroids alone. In each group 51.6 per cent and 50 per cent of patients respectively improved with treatment. The outcome of treatment is also not influenced by endoscopic abnormality. The difference was not statistically significant (p = 0.86). The study indicates that half of patients with chronic sinusitis will improve with medical treatment but the addition of antral washout confers no additional benefits.     

竞争环境下电信行业的普遍服务

以引入竞争为标志的电信领域改革以来，在竞争环境下如何实现作为原有垄断经营者政治使用命的普遍服务，成了世界各国政府，企业，学术界及国际电信机构共同关注的重大问题，我国是个发展中国家，电信的普通服务远没有完成。因此在借鉴国外经验的基础上，研究和探讨竞争环境下实现普遍服务的政策和策略具有十分现实的意义。